This is a request for a Total Internal Reflection Fluorescence (TIRF) microscope system designed to image the adherent surface of cells and adjacent cortical cytoplasm at unprecedented sensitivity and resolution. This integrated system is built around a standard epifluorescence microscope and includes a TIRF attachment, selectable three line laser input, optimized high numerical aperture objectives for TIRF, precision Z-axis controller, time-lapse capability, cooled CCD camera, and image acquisition and processing software. The system will extend the capability of the major and minor user groups and others at the University to explore both structural and dynamic features of the bottom surface of cells where many of the dynamic adhesive, cytoskeletal and membrane activities of the cell are focused. The users are divided into a major user group and a minor user group. The major user group is comprised of four laboratories that share an interest in exploring events at the cell-substratum interface as related to basic questions in cell migration and motility and have collaborate on projects in the past. The minor user group consists of five laboratories pursuing questions of membrane, cytoskeletal and vesicle trafficking dynamics that are related to neuronal cell function. By grouping the major and minor users by shared research interests, it is anticipated that a synergy will develop in how TIRF microscopy can best be applied to research problems that are common to the groups. Both users groups have extensive experience in traditional epifluorescence and confocal microscopy approaches, but have found that that these approaches are limited when it comes to imaging the very bottom of the cell where so much of the cell's activity is directed. The major user group has found in initial studies that TIRF microscopy, with its high signal-to-noise and ability to image a very narrow section of the adherent surface of migrating ceils, provides a particularly powerful approach to resolving questions that related to this critical part of the cell. These initial studies have also lead to new collaborative projects within the group. Since none of the members of either group currently has access to a TIRF microscope, the addition of a TIRF microscope will dramatically enhance both groups ability to tackle projects already underway and to initiate new projects related to basic cell migration and neurobiology. [unreadable] [unreadable]